Efficient Annealing-Free P3HT:PC₆₁BM-Based Organic Solar Cells by Using a Novel Solvent Additive without a Halogen or Sulphur Atom

The power conversion efficiency (PCE) of poly(3-hexylthiophene) (P3HT) and 6,6-phenyl C61-butyric acid methyl ester (PC₆₁BM) based organic solar cells (OSCs) is significantly improved by using benzyl acetate (BA), an organic compound without any halogen or sulphur atom, as a processing additive to control the blend morphology. The solar cells show PCE of 3.85% with a fill factor (FF) of 65.22%, which are higher than those of the common thermal annealing device (PCE 3.30%, FF 60.83%). The overall increased PCE depends upon the enhanced crystallinity of P3HT and good carriers transport, with a high balanced charge carrier mobility.